1. Field of the Invention
The present invention relates to compressed air tanks, and more specifically relates to automatically purging water and other contaminants from compressed air tanks.
2. Description of Related Art
Compressed air is used in a variety of applications. One example is pneumatic braking systems on vehicles such as buses, trucks, trailers, construction equipment, and recreational vehicles. To compress the air, an air compressor receives power from the engine of the vehicle and compresses air from the ambient environment into an air pressure tank or reservoir. The process of compressing air causes water vapor, oil, and other contaminants to collect in the bottom of the air pressure tank. If these contaminants are not removed from the air pressure tank on a regular basis, the contaminants can damage the air pressure tank or enter the braking system and damage the braking components.
Conventional air pressure tanks include a manual drain valve to remove contaminants from the air pressure tank. In a vehicle braking system, the driver of the vehicle should open the drain valve on a regular basis (e.g., whenever the engine is turned off). However, drivers often do not drain the contaminants from the air tank on a regular basis which can cause damage and the need for expensive repairs to the air tank and braking system.
Automatic purge valves have been developed to automatically purge the contaminants from the air tank based upon the occurrence of a specific event (e.g., air compressor turning on/off, ignition turning on/off, and periodic timer expiring). However, each known automatic purge valve requires electrical power or a connection to the air compressor to activate the automatic purge valve. There are situations and applications where the known automatic purge valves are inoperable because the air pressure tanks do not have access to electrical power or the air compressor (e.g., air pressure tanks on trailers).